TSPAN1 and prostate cancer: To examine TSPAN1 protein expression in clinical prostate cancer tissue we further showed that staining by this antibody was blocked by pre-incubation with a blocking peptide (Supplementary Figure 2C) and by detection of siRNA mediated protein depletion by immunohistochemistry in Formalin Fixed Paraffin Embedded (FFPE) cell pellets (Supplementary Figure 2D).